[CI] We need to shard ci_qemu tests

[mehrdadh]

Working on this PR: #11809
This will increase the workload on ci_qemu and it has timeout issue. So it's time to shard this image like others.

cc @Mousius @areusch @driazati

[areusch]

cc @gigiblender can you take a shot at this one? here are some PRs for inspiration:

• first you need to fix up the test script to support sharding similar to https://github.com/apache/tvm/pull/10413/files
• next you need to modify the Jenkinsfile to create 2 shards. there's not a PR that's done this from scratch yet, but there is an example of adding shards. it should be fairly straightforward once it's clear what to do here.

also cc @driazati